So I have been off cigs for about 2 yrs now and vaping. For some reason i have been huffing up tan/brown phlegm from throat and its thick. I have been to 2 drs and sont find anything abnormal. I can run fine in my daily exercise routine and the only question I have is if anyone else has had this problem, i have heard nic oxidizes and turns brown when comong in contact with oxygen. Wouldnt it be reasonable to say that the juice is oxydizing thus giving that tan color to phlegm sometimes. Ususally its clear but when it sits there for a while get that yellow/tan hue to it. Any insight would help. Again i already been to Drs.